Two young elephants greet each other in Kenya's Samburu National Reserve
George Wittemyer
Elephants may be the only animals other than humans that give each other random names, according to a machine learning analysis of recordings.
The analysis revealed that the African savanna elephant (African brown) appears to contain a name-like element that is unique to certain individuals. Moreover, those individuals know their own names and respond more strongly than others when a call addressed to them is played over a speaker.
“For years we've observed that when elephants make contact calls, one elephant in the group will raise his head, listen and respond,” says Joyce Poole. Elephant Voice“And the other elephants seemed to be ignoring him, so we wondered if the call was directed at one particular individual,” said Bryan G. Gregg, a small organization that aims to study and protect elephants.
More than 600 recordings made by Poole and others are currently being analyzed. Michael Pardo Researchers at Colorado State University applied the recordings to analyze elephant calls, including contact calls made when an elephant moves out of sight and greeting calls made when an elephant approaches another. The researchers knew which individual called out to each elephant and responded to each call.
The team's software was able to predict which individual was being spoken to in a quarter of cases, doing much better than chance.
The researchers then played some of the rumbling sounds to elephant pairs, including one that was “named,” and found that the named elephant responded more strongly, approaching the speaker faster, making quicker responses, and emitting more calls than its unnamed counterpart.
Dolphins and some bird species have been known to mimic the calls of calling animals to attract specific individuals. Elephants can learn to imitate soundsHowever, the team found no evidence that the elephants were imitating each other.
In other words, they appear to use arbitrary sounds as names, just like humans do, Poole said.
The analysis revealed whether different elephants share the same names for certain individuals, and each elephant may have its own unique name for the others.
“We have official names, but different people may call the same person by different nicknames,” Poole said. “That could be it. I guess we just don't know yet.”
“This is a very interesting study because there is evidence suggesting that not only do African elephants produce individual-specific vocalizations – which is commonly reported in many species – but, more importantly, that they respond specifically when they hear individual-specific vocalizations made by other elephants,” he says. Daniel Blumstein At the University of California, Los Angeles.
“The idea that elephants can use individually distinct vocalizations to attract specific individuals is novel and provocative, opening the door to a more nuanced understanding of the rich social lives of these animals,” he says.
“I think this result is very reasonable.” Torsten Balsby At Aarhus University in Denmark.
Balsby studies parrots that live in much larger groups, and he notes that learning names would be much harder in a large group of hundreds or thousands of birds. “Mimicking talking to other individuals is a simpler solution that doesn't require prior interaction,” he says.
A 2005 study reported that captive green parrots “vocally label” — or give names to — their peers, Balsby says. But they did so with different versions of contact calls, “so it may not be as arbitrary as elephants',” Balsby says.
Poole believes her work is just the beginning in understanding elephant communication: “Elephant communication has many complex layers that will take time to unravel, so I expect there will be many more exciting discoveries to come in the coming years,” she says.
For example, she thinks elephants might use place names: “When elephants make 'let's go' rumbles to indicate to other elephants in the herd which way they want to go, they may actually be telling them exactly where they want to go,” Poole says.
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Source: www.newscientist.com
